The inventive concept relates generally to electronic memory technologies. More particularly, certain embodiments of the inventive concept relate to nonvolatile memory devices and related methods of operation.
Semiconductor memory devices can be roughly divided into two categories according to whether they retain stored data when disconnected from power. These categories include volatile memory devices, which lose stored data when disconnected from power, and nonvolatile memory devices, which retain stored data when disconnected from power. Examples of volatile memory devices include static random access memory (SRAM) and dynamic random access memory (DRAM). Examples of nonvolatile memory devices include masked read-only memory (MROM), programmable ROM (PROM), erasable programmable ROM (EPROM), and electrically erasable programmable ROM (EEPROM).
Flash memory is a popular form of EEPROM that can be found in a wide variety of modern electronic devices, such as computers, cellular phones, a personal digital assistants (PDAs), digital cameras, camcorders, voice recorders, MP3 players, handheld PCs, gaming machines, facsimile machines, scanners, and printer, to name but a few. The popularity of flash memory can be attributed to a variety of features, such as its relatively high storage capacity, performance, and durability, as well as its relatively low power consumption and cost.
In an effort to provide even better performance, storage capacity, and so on, researchers continue to devote significant resources to the further development of flash memory technology. One example of this further development is the introduction of flash memory devices comprising memory cells formed in three-dimensional (3D) arrays. These devices have the potential for significantly greater storage capacity and performance compared with flash memory devices where memory cells are formed in two-dimensional (2D) arrays. Nevertheless, the development of the 3D array technology has presented a number of technical challenges and opportunities to be addressed through ongoing innovation.